Place olive oil, lemon juice and plum tomatoes in a large mixing bowl. Add cous cous and mix thoroughly. There is no cooking, so it important that you have an excessive amount of liquid in the bowl. The juice from the tomato with oil will "cook" the cous cous. The cous cous will absorb all the liquids, puff up and become very tasty. Add red onions, red and yellow peppers, cherry tomatoes and fresh torn basil to the bowl. Mix well. Let sit in the refrigerator for a few hours for all the flavors to combine. Makes 4 servings.